Cover-glass for automobile-headlights.



. W. CHURCH|LL. COVER GLASS FOR AUTOMOBILE HEADLIGHTS.

P LICATION FILED DEC. 3| 19H.-

Patenteul June 118,, 191

'WILLIAM CHURCHILL, OF CORNING, NEW YORK, ASSIGNOR 'lO CORNING GLASS WORKS, 01E COR-MING, NEZU YORK, A CORPORATION OF NEW YORK.

CQVER-GLASS FDR AUTOMOBILE-HEADLIGHTS.

1,269,? incl,

To all whom it may concern:

lie it known that l, \VILLIAM CHURCHILL, a citizen of the United States of America, and a resident of Corning, New York, have invented certain new and useful Improve-- ments in Cover-Glasses for Automobile- Headlights, of which the following is a specification.

This application is filed as a division of my application Serial. No. 142,094, filed January 12, 1917, for katadioptric projectors and has for its purpose to cover one form of headlight glass shown therein.

It has been heretofore proposed to place on a cover glass a series of prisms so calculated and arranged that light passing therethrough from the l ght source and reflector is bent downwardly, and prevented from upward projection into the eyes of the approaching driver. In the present invention l: utilize such prisms together with raisins placed thereon and adapted to prduce a side spread of the rays passing therethrough, for the purpose of giving side illumination and also adapted to produce down ward. divergence of such rays. For this purpose my invention consists in arrangements and. combinations of the several parts such as will be hereinafter more fully described and claimed.

Referring to the accompanying drawings in which corresponding parts are designated by corresponding marks of reference,-

Figure 1 is a rear view of a cover glass made in accordance with this invention.

Fig. 2 is a fragmental but enlarged vertical section thereof.

Fig. 8 is a horizontal section thereof.

The cover glass has formed on the rear face thereof a series of prisms C whose bases are downward and which may be, as shown, horizontal. By preference, as shown, this is done by stepping the inner faces of a cover glass into a series of horizontal zones, each zone having a lower face 0 and an inclined face 0 arising therefrom and extending to the base or lower face of the zone located thereabove. This is well known in. the art. By preference, moreover, the angle formed between the inner faces C and the optical axis of the system varies in different parts of each zone. as is described in my original application above refcrrcdto in such a way that an increased corrective Specification of Letters Patent. jlPwbgnt gdl Junie 1L8, 191%.,

Uriginal application filed January 12, 191'2, Serial No. 142,094. Divided and this appIication filed December- Serial No. 205,221.

value is given to the central portions of the several zones over that given to the ends thereof which results in causing each prism to be somewhat concentrating in respect to the lateral spread, and for the purpose of neutralizing or overcoming this as may be desired, and to give side illumination, which is sometimes desirable, I may, if I desire, form upon the cover glass and specifically and preferably on the central part thereof, a series of ribs F having lateral difiusive power.

By preference, these ribs are, as illustrated, superposed on the prisms, having their major axes at right angles to the length of the latter; each rib being in the form of an ungula, whose refractive face is in vertical. section inclined to the plane of the cover glass at a greater angle than is the prism face 0 on which it is imposed, or in other words having a greater thickness at the bottom than the top. The ribs can conveniently be formed as cylindrical ungulas, the cylindrical axes f f of which are at an angle of 2 degrees to the underlying prism. Between these ribs will be -spaces formed by the faces 0 of the prisms, the light passing through which will not be diffused. As the ribs cause a downward defiection of light passing therethrough, in order to obtain the same average vertical distribution I may reduce the corrective ower of the prisms themselves.

It will be understood that by the changes in the radius of curvature of the ribs, the amount of side divergence may be con trolled, while the amount of light so spread will depend on how much of the face of the cover glass is covered by the ribs, but in any event the use of the ribs of the character indicated will result in non-diffusive faces iocatcd on each prism in alternation with the ribs.

In my original application before referred to I have shown, described and claimed prisms having greater corrective value at their center than at their ends, but inasmuch as the ungulas hereinbefore described are of value irrespective of peculiar optical properties of the prisms upon which they are superimposed, it do not limit my invention to the combination of any specific class of prisms, except in so far as the claims themselves may introduce such limitation 20 lights having Having thus described my invention, what I claim as new and desire to secure by Letters Patent is,

1. A cover glass having thereon'a series 5 of prisms to produce a downward bending of rays passing therethrough, and having superimposed upon the retracting faces of such prisms ungulas, the axes of such ungulas being at anangle to such retracting faces. 2. A cover glass having thereon a series of prisms to produce a downward bending of rays passing therethrough, and having a series of ungulas, the outer faces of which are inclined to the faces of the prisms, the vungulas being so placed upon the cover glass that rays passing thereth'rough are given a downward deflection both by the ungulas and by the prisms.

3. A cover glass for automobile heada series of prisms thereon to produce a downward bending of the rays passing therethrough, and having on the prisms ribs forming ungulas of greater depth at the bottom than at the top to 2 produce side divergence.

cover glass for automobile headlights having a series of prisms thereon to produce downward bending of the rays passing therethrough, and at different points thereon ungulas of greater depth at the bottom than at the top to produce side divergence, and in connection with the prisms to produce downward divergence.

5. A transparent cover for a headlight having thereon a series of prisms to produce 1 a downward bending of rays passing therethroug and having superimposed upon the retracting faces of such prisms ribs, the axes of such ribs being at an angle to such refracting faces.

6. A transparent cover for a headlight having thereon a, series of prisms to produce a downward bending of rays passing therethrough, and having a seriesof vertical ribs, the outer edges of which are inclined to the face of the prisms.

7. A transparent cover for a headlight having a series of prisms thereon to produce a downward bending of rays passing therethrough, and having on these prisms ribs having greater depth at their bottom than at their top to produce an additional downward bending of the rays and a side (livergence thereof.

In testimony whereof I have signed my' name this 29th day of October 1917.

' WILLIAM CHURCHILL.

Witnesses:

ANNA MARGARET HAAR, EUGENIE HAAR.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

